Conventionally, rotary measuring devices that measure the weight of an object while causing the object to rotate have been utilized. In such rotary measuring devices, oftentimes a load cell having a measuring function is attached below a measuring plate or a belt conveyor on which the object is placed, and the load cell measures the load that the load cell receives while rotating together with the object. At this time, not just the total weight of the weight of the tare such as a measuring plate and the weight of the object, but also error resulting from rotation is included in the measured value outputted from the load cell.
An example of error resulting from rotation will now be explained. For example, as shown in FIG. 1, a case will be considered where a load cell 27 has a structure including a free end 17 and a fixed end 18. In this case, in the vicinity of the free end 17 of the load cell 27, the weight of the tare such as a measuring plate 25 and the weight of an object are loaded, whereby angular displacement occurs with respect to the horizontal plane. When the tare and the object rotate in a state where such angular displacement is occurring, a force FL acting on the load cell 27 also slants at an angle θ with respect to the radial direction so as to counter a centrifugal force FC acting on the tare and the object. Additionally, as a result, a force FE of a size of |FC|tan θ is loaded in the vertical direction on the load cell 27 as error resulting from rotation.
Japanese Patent No. 2,794,472 discloses an aspect where the weight of an object is measured in consideration of the aforementioned error (called “centrifugal force error” below) resulting from rotation which occurs stemming from centrifugal force.